In what is thought to be a world-first, a British woman who was given an ovary transplant is about to give birth to her first baby.
The 38-year-old Londoner underwent the pioneering whole ovary transplant in the U.S. early last year when her identical twin sister's donated ovary was transplanted after being removed using keyhole surgery.
The transplant was carried out by Dr. Sherman Silber and his team at the Infertility Centre of St Louis in Missouri and is the first to result in a successful pregnancy.
The woman's ovaries stopped working when she was 15, when she experienced a premature menopause and stopped producing hormones and she has become pregnant a year after receiving her sister's ovary.
According to Dr. Silber identical twins are five times more likely than the rest of the female population to suffer ovary damage and his pioneering new procedure is particularly relevant for them.
As the twins are genetically identical, eggs from the donor ovary are equivalent to those produced by the patient herself - women who are not genetically identical produce genetically different eggs so the transplant technique will have limited application for women who are not twins.
However it does offer the possibility of removing and freezing an ovary prior to cancer treatment such as radiotherapy and chemotherapy.
The transplantation of the walnut-sized ovary demanded microsurgery to reconnect blood vessels as small as half a millimeter in diameter and follows previous successes by the team with ovary graft transplants, where a slice of ovary tissue is grafted onto an infertile patient's own ovary.
The first graft transplant to produce a successful pregnancy was in 2004 and was also between twin sisters.